Basic Training

ISUOG Basic TrainingMaking a Decision – Normal or Not?

Basic Training

At the end of the lecture you will be able to:

• Describe how to perform a transverse overview/sweep of

the fetal body from neck to sacrum

• Recognise the differences between the normal & most

common abnormal ultrasound appearances that can be

excluded by the transverse overview/sweep

Learning objectives

Basic Training

1. What probe movements are required to perform a transverse overview/sweep of the fetal body correctly?

2. Which parts of the fetal anatomy are best assessed using this overview/sweep?

3. What are the key ultrasound features that distinguish between the correct & the incorrect view of a vertebra in cross section

4. Which abnormalities should be excluded after performing a transverse overview/sweep correctly?

Key questions

Basic Training

Transverse sweep – overview 2

Transverse sweep from

neck to sacrum

• Full assessment of

thorax, abdomen & pelvis

• Visualisation of the

vertebrae

• Anatomical landmarks

Slide, rotate,

Slide, rotate, slide

Basic Training

Anatomical landmarks – overview 2

Transverse sweep from

neck to sacrum

• Full assessment of

thorax, abdomen &

pelvis

• Visualisation of the

vertebrae

Basic Training

Transverse sweep – overview 2

Basic Training

Transverse sweep- overview 2

• Slide from the head down to

the sacrum

• Ideal position for spine,

however no fluid between

spine & uterine wall

Basic Training

Transverse sweep- overview 2

• Ideal position for spine,

but sparse fluid between

spine & uterine wall

Basic Training

Transverse sweep- overview 2

• Good position for spine,

& with fluid between

spine & uterine wall

Basic Training

Transverse sweep- overview 2

• Good position to

observe spine, thorax

& abdominal

structures

Basic Training

Transverse sweep- overview 2

• Poor visibility of the

spine

• Good position to

observe thorax &

abdominal structures

Basic Training

Spina bifida

• The vertebrae become U-shaped

instead of their normal triangular form

• Neural tissue is protruding

Basic Training

Spina bifida

Confirm any anomaly in more than 1 plane

Basic Training

Transverse sweep - overview 2 thorax

What you can exclude:

• Situs anomalies

• AVSD

• Univentricular heart

• Ectopia cordis

• Significant pericardial effusion, > 4mm

Basic Training

Transverse sweep - overview 2 thorax

Confirm in 2 planes

What you can exclude:

• CPAM

• Left sided diaphragmaic hernia

• Significant pleural effusion

>4mm

• Skin oedema

• Spina bifida

Basic Training

Transverse sweep - overview 2 abdomenWhat you can exclude:

• Situs abnormalities

• Ascites

• Small/absent stomach

• Duodenal atresia

• Echogenic bowel*

• Gastroschisis /

omphalocele

*

Basic Training

Transverse sweep- overview 2 abdomen

What you can exclude:

• Bilateral renal agenesis

• Cystic renal dysplasia

• Lower urinary tract obstruction

• Renal pelvis dilatation

• 2 vessel cord

• Sacrococcygeal teratoma

Basic Training

Making a decisionWhen encountering a structure or measurement not compatible with normal views & biometry:

• Confirm in more than 1 plane

• Confirm measurement at least twice – consider if in correct plane

• Continue to complete the ultrasound scan & assess whether the abnormal structure / measurement can be reproduced

• Share with parents your concern the fetus may not be normal only when the scan is finished

• Request opinion of your supervisor

Basic Training

Making a decision

• Is this posterior horn measurement >10 mm?

9.6 -9.9 mm 10.4 mm10 mm

Basic Training

Making a decision

• Is the stomach absent?

Reassess after 10-20 minutes

Basic Training

Making a decision• Is the bowel echogenic?

• Look at BMI:– Low BMI & posterior placenta may cause a too perfect view

– Turn down the gain to assess whether bowel as bright as bone

Not echogenic

Basic Training

1. When performing the transverse sweep, the position of

the spine is vital for the evaluation of anatomical

structures

2. The spine should appear as 3 ossified centres in a

triangular shape, covered by skin

3. When the 3 ossified centres appear U-shaped, think of

spina bifida & confirm the anomaly in multiple planes

Key points

Basic Training

4. When encountering an abnormal appearance or measurement continue to complete the scan, confirm in multiple planes & with multiple measurements, before communicating with the parents your final decision to refer

5. It is not your role to make a diagnosis, but you should be familiar with the range of normal appearances

6. Whenever you are in doubt refer

Key points

Basic Training

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